Non-contacting dynamic seal

ABSTRACT

A seal for a gas turbine engine includes a full hoop outer ring, a shoe coupled to the full hoop outer ring via an inner beam and an outer beam, and a wave spring in contact with at least one of the inner beam or the outer beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, and thebenefit of U.S. application Ser. No. 14/852,838, entitled“NON-CONTACTING DYNAMIC SEAL,” filed on Sep. 14, 2015, which is anonprovisional of, and claims priority to, and the benefit of U.S.Provisional Application No. 62/063,705, entitled “NON-CONTACTING DYNAMICSEAL,” filed on Oct. 14, 2014, which is hereby incorporated by referencein its entirety.

FIELD

The disclosure relates generally to gas turbine engines, and moreparticularly to seals in gas turbine engines.

BACKGROUND

Gas turbine engines typically comprise seals located around rotatingcomponents. The seals may prevent movement of fluid, such as air,between locations on opposite sides of the seal. One type of seal usedin gas turbine engines is a conventional non-contacting dynamic seal,such as a HALO seal manufactured by Advanced Technologies Group, Inc.The non-contacting dynamic seals may decrease the amount of leakageacross the seal. Additionally, the non-contacting dynamic seals may besensitive to engine vibrations and require damping.

SUMMARY

A non-contacting dynamic seal may comprise a full hoop outer ring, ashoe, and a wave spring. The shoe may be coupled to the full hoop outerring via an inner beam and an outer beam. The wave spring may be incontact with at least one of the inner beam or the outer beam.

In various embodiments, the wave spring may be located between the innerbeam and the outer beam. The wave spring may be located between the shoeand the inner beam. The wave spring may be located between the outerbeam and the full hoop outer ring. The wave spring may comprise at leastthree antinodes. The antinodes may be configured to slide against atleast one of the inner beam or the outer beam in response to a vibrationin the non-contacting dynamic seal. The wave spring may comprise atleast one of a cobalt alloy or a nickel alloy. The non-contactingdynamic seal may comprise a plurality of inner segments, wherein eachinner segment comprises a respective wave spring.

A seal assembly for a gas turbine engine may comprise an outer ring, ashoe, a first beam and a second beam, and a first wave spring. The shoemay be coupled to the outer ring. The shoe may be configured to moveradially with respect to the outer ring. The first beam and the secondbeam may couple the shoe to the outer ring. The first wave spring may belocated between the first beam and the second beam. The first wavespring may be configured to damp vibrations in the first beam and thesecond beam.

In various embodiments, the seal assembly may be a non-contactingdynamic seal. The first wave spring may comprise a first antinode and asecond antinode in contact with the first beam, and a third antinode incontact with the second beam. The first antinode and the second antinodemay be configured to slide against the first beam in response to avibration in the first beam. A second wave spring may be between thefirst beam and the second beam. A third wave spring may be between thefirst beam and at least one of the shoe or the outer ring. The firstwave spring may comprise at least one of cobalt alloy and nickel alloy.

A method of damping vibrations in a seal may comprise inserting a firstwave spring between a first beam and a second beam of the seal. Invarious embodiments, the wave spring may comprise a first antinode and asecond antinode in contact with the first beam, and a third antinode incontact with the second beam. The wave spring may comprise a firstantinode and a second antinode in contact with the first beam, and athird antinode in contact with the second beam. The method may compriseconfiguring the first antinode and the second antinode to slide againstthe first beam. The seal may be a non-contacting dynamic seal. Themethod may comprise inserting a second wave spring between the secondbeam and a shoe of the seal.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures.

FIG. 1 illustrates a schematic cross-section view of a gas turbineengine in accordance with various embodiments;

FIG. 2 illustrates a perspective view of a non-contacting dynamic sealin accordance with various embodiments;

FIG. 3 illustrates a cross-section view in an axial direction of anon-contacting dynamic seal comprising a wave spring in accordance withvarious embodiments;

FIG. 4 illustrates a cross-section view in a circumferential directionof a non-contacting dynamic seal comprising a wave spring in accordancewith various embodiments;

FIG. 5 illustrates a cross-section view in an axial direction of anon-contacting dynamic seal comprising a plurality of wave springs inaccordance with various embodiments; and

FIG. 6 illustrates a process for damping vibrations in a seal.

DETAILED DESCRIPTION

The detailed description of various embodiments herein makes referenceto the accompanying drawings, which show various embodiments by way ofillustration. While these various embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical, chemical, and mechanical changes may be madewithout departing from the spirit and scope of the disclosure. Thus, thedetailed description herein is presented for purposes of illustrationonly and not of limitation. For example, the steps recited in any of themethod or process descriptions may be executed in any order and are notnecessarily limited to the order presented. Furthermore, any referenceto singular includes plural embodiments, and any reference to more thanone component or step may include a singular embodiment or step. Also,any reference to attached, fixed, connected, or the like may includepermanent, removable, temporary, partial, full, and/or any otherpossible attachment option. Additionally, any reference to withoutcontact (or similar phrases) may also include reduced contact or minimalcontact.

Referring to FIG. 1, a gas turbine engine 100 (such as a turbofan gasturbine engine) is illustrated according to various embodiments. Gasturbine engine 100 is disposed about axial centerline axis 120, whichmay also be referred to as axis of rotation 120. Gas turbine engine 100may comprise a fan 140, compressor sections 150 and 160, a combustionsection 180, and turbine sections 190, 191. Air compressed in thecompressor sections 150, 160 may be mixed with fuel and burned incombustion section 180 and expanded across the turbine sections 190,191. The turbine sections 190, 191 may include high pressure rotors 192and low pressure rotors 194, which rotate in response to the expansion.The turbine sections 190, 191 may comprise alternating rows of rotaryairfoils or blades 196 and static airfoils or vanes 198. Cooling air maybe supplied to the turbine sections 190, 191 from the compressorsections 150, 160. A plurality of bearings 115 may support spools in thegas turbine engine 100. FIG. 1 provides a general understanding of thesections in a gas turbine engine, and is not intended to limit thedisclosure. The present disclosure may extend to all types of turbineengines, including turbofan gas turbine engines and turbojet engines,for all types of applications.

The forward-aft positions of gas turbine engine 100 lie along axis ofrotation 120. For example, fan 140 may be referred to as forward ofturbine section 190 and turbine section 190 may be referred to as aft offan 140. Typically, during operation of gas turbine engine 100, airflows from forward to aft, for example, from fan 140 to turbine section190. As air flows from fan 140 to the more aft components of gas turbineengine 100, axis of rotation 120 may also generally define the directionof the air stream flow.

Referring to FIG. 2, a perspective view of a non-contacting dynamic seal(“NCDS”) 200 is illustrated according to various embodiments. The NCDS200 may comprise a full hoop outer ring 210 and a plurality of innersegments 220. The NCDS 200 may circumscribe a rotating component, suchas a rotor shaft. The NCDS 200 may form a seal around the rotatingcomponent without contacting the rotating component. A thin air cushionmay be formed between the inner segments 220 and the rotating componentwhich prevents contact between the inner segments 220 and the rotatingcomponent. The rotating component may radially expand or contract withchanges in temperature, and an increase in air pressure between therotating component and the inner segments 220 may cause the innersegments 220 to move radially inward or outward in response to thechange in size of the rotating component. Each inner segment 220 maycomprise a wave spring, as further described with reference to FIGS.3-5.

Referring to FIG. 3, a cross-section view of an inner segment 220 ofNCDS 200 is illustrated according to various embodiments. X-y axes areprovided for ease of illustration, with a direction in the negative ydirection referred to as radially inward and a direction in the positivey direction referred to as radially outward. The inner segment 300 maycomprise a shoe 310 coupled to the outer hoop 320 via an inner beam 330and an outer beam 340. A thin layer of air may form between the shoe 310and a rotating component 350. The thin layer of air may prevent contactbetween the shoe 310 and the rotating component 350. As the rotatingcomponent 350 expands or contracts, the shoe 310 may move radiallyoutward or radially inward by a corresponding amount. The inner beam 330and the outer beam 340 may allow the shoe 310 to move radially inward oroutward without tilting in the e direction.

During testing of the NCDS 200, it was discovered that vibrational wavesmay exist in the inner beam 330 and the outer beam 340. The vibrationalwaves may cause fatigue of the inner beam 330 or the outer beam 340.Fatigue of the inner beam 330 or outer beam 340 could result in reducedsealing effectiveness and durability of the NCDS 200.

A wave spring 360 may be inserted in the NCDS 200. In variousembodiments, the wave spring 360 may be located between the shoe 310 andthe inner beam 330, between the inner beam 330 and the outer beam 340,and/or between the outer beam 340 and the outer hoop 320. Any number ofwave springs may be utilized.

Each wave spring may comprise at least three antinodes. For example,wave spring 360 comprises a first antinode 362 in contact with the outerbeam 340, a second antinode 364 in contact with the inner beam 330, anda third antinode 366 in contact with the outer beam 340. However, invarious embodiments, wave spring 360 may comprise any suitable number ofantinodes. In various embodiments, wave spring 360 may comprise at leastone of a nickel alloy and/or a cobalt alloy. However, wave spring 360may comprise any suitable material.

In response to vibration of the inner beam 330 or the outer beam 340,the distance D1 between the inner beam 330 and the outer beam 340 maychange. In response to the distance D1 decreasing, the inner beam 330and the outer beam 340 may compress the wave spring 360. As the wavespring 360 compresses, the length L of the wave spring 360 may increase.The increase in the length L may cause the first antinode 362 to slideagainst the outer beam 340 in the negative x-direction, and the thirdantinode 366 to slide against the outer beam 340 in the positivex-direction. The friction from the sliding contact may dissipate energyin the vibrations of the inner beam 330 and/or the outer beam 340. Thus,the wave spring 360 may damp vibrations in the inner beam 330 and theouter beam 340, which may prolong the lifetime of the NCDS 200.

Referring to FIG. 4, a cross-section view of an NCDS 400 in thecircumferential direction is illustrated according to variousembodiments. The NCDS 400 may comprise a shoe 410, a full hoop outerring 420, an inner beam 430, and an outer beam 440. The shoe 410 may beseparated from a rotating component 450 by a thin layer of air. Theparticular design of the shoe 410, such as knife edges 412, may assistin creating the thin layer of air and maintaining separation fromrotating component 450.

NCDS 400 is shown located within a static seal support 470. An L-support472 and a retention mechanism 474 may hold the NCDS 400 between theL-support 472 and one or more seal plates 476. A split lock ring 478 mayhold the assembly within the static seal support 470.

A wave spring 460 may be located between the inner beam 430 and theouter beam 440. The wave spring 460 may damp vibrations in the innerbeam 430 and the outer beam 440. In various embodiments, the wave spring460 may be located between the outer beam 440 and the full hoop outerring 420, or between the inner beam 430 and the shoe 410.

Referring to FIG. 5, a cross-section view of an inner segment 500 havingmultiple wave springs is illustrated according to various embodiments.Inner segment 500 may comprise a first wave spring 561 and a second wavespring 562 located between the shoe 510 and the inner beam 530, a thirdwave spring 563 and a fourth wave spring 564 located between the innerbeam 530 and the outer beam 540, and a fifth wave spring 565 and a sixthwave spring 566 located between the outer beam 540 and the full hoopouter ring 520. One skilled in the art will recognize that any number ofwave springs may be utilized in inner segment 500.

Referring to FIG. 6, a flowchart 600 of a process for damping vibrationsin a seal is illustrated according to various embodiments. A seal may beprovided (step 610). The seal may comprise a first beam and a secondbeam. In various embodiments, the seal may be a non-contacting dynamicseal. A wave spring may be inserted between the first beam and thesecond beam (step 620). In various embodiments, one or more springs maybe inserted between the first beam and the second beam, between thefirst beam and a full hoop outer ring, and/or between the second beamand a shoe of the seal. The wave spring may be configured to slideagainst at least one of the first beam and the second beam (step 630).The sliding may damp vibrations in the seal.

Although described herein primarily with reference to non-contactingdynamic seals, wave springs may be utilized to damp vibrations invarious different seals, such as brush seals or carbon seals. The wavespring may generally transfer displacement of a seal component intospring motion and friction.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure. The scope of the disclosure is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”,“various embodiments”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is intended to invoke 35 U.S.C.112(f) unless the element is expressly recited using the phrase “meansfor.” As used herein, the terms “comprises”, “comprising”, or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises a list ofelements does not include only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus.

1. A seal for a gas turbine engine comprising: a full hoop outer ring; ashoe coupled to the full hoop outer ring via an inner beam and an outerbeam; and a wave spring in contact with at least one of the inner beamor the outer beam.
 2. The seal of claim 1, wherein the wave spring islocated between the inner beam and the outer beam.
 3. The seal of claim1, wherein the wave spring is located between the shoe and the innerbeam.
 4. The seal of claim 1, wherein the wave spring is located betweenthe outer beam and the full hoop outer ring.
 5. The seal of claim 1,wherein the wave spring comprises at least three antinodes.
 6. The sealof claim 5, wherein the antinodes are configured to slide against atleast one of the inner beam or the outer beam in response to a vibrationin the seal.
 7. The seal of claim 1, wherein the seal is anon-contacting dynamic seal.
 8. The seal of claim 1, further comprisinga plurality of inner segments, wherein each inner segment comprises arespective wave spring.
 9. The seal of claim 1, wherein the shoe isconfigured to move radially with respect to the outer ring.
 10. The sealof claim 9, wherein the inner beam is disposed radially from the outerbeam.
 11. The seal of claim 10, wherein the wave spring is locatedradially between the inner beam and the outer beam.
 12. The seal ofclaim 10, wherein the wave spring is located radially between the shoeand the inner beam.
 13. The seal of claim 10, wherein the wave spring islocated radially between the outer beam and the full hoop outer ring.